Time delay power control system and apparatus



Jan. 12, 1937. R. J. PLAISTED 2,057,413 TIME DELAY POWER CONTROL SYSTEM AND APPARATUS Filed Oct; 22, 1954 I RECTIFIER. 30.,

INVENTOR. 35 Pass J P/azsleo. 34 BY 30 r ATTORNEY Patented Jan. 12, 1937 UNITED STATES 1 TIME DELAY POWER CONTROL SYSTEM AND APPARATUS Ross J. Plaisted, Brecksville, Ohio, assi'gnor to Aircraft Service, Inc., Cleveland, Ohio, a corporation of Ohio Application October 22, 1934, Serial No. 749,498

- 4 Claims. (01. 175-320) This invention relates to electrical systems and apparatus for efiecting the application of power in response to variations of a fluctuating variable factor and for rendering ineffective fluctuations 5 of less than predetermined minimum duration.

The invention has particular application to the intermittent application of power to move a massive wind T at an airport to maintain it in true wind-direction-indicating position in response to changes of position of a pilot wind vane fluctuatingl-y movable by wind gusts and wherein the T is prevented from responding to changes of position of the vane enduring for less than a predetermined time interval.

Among the objects of the invention are:

To provide generally an improved electrical system and apparatus of the class referred to;

To provide an improved control system and apparatus for determining the position of airport wind-direction-indicating Ts;

To provide an improved time interval producing means;

To provide an improved electric system and apparatus for producing predetermined time intervals;

To provide an improved electric control system and apparatus for repeatedly initiating the running of a time interval at each of the successive fluctuations of a fluctuatingly movable element and for effecting the application of power upon the duration of the time interval beyond a predetermined minimum.

My invention is fully disclosed in the following description taken in connection with the accompanying drawing in winch: a

Fig. 1 is a diagrammatic representation of an apparatus and electrical system embodying my invention as applied to the control of a wind-direction-indicating T at an airport;

Fig. 2 is a view similar to a part of Fig. 1 illustrating a modification.

In the drawing at I is indicated a massivewind T disposed generally parallel to the ground, large enough to be plainly seen at relatively great elevation by aviators in the air, and generally simulating by the stem 2 and head 3 the fuselage and wings of an airplane whereby its directional position may indicate to an aviator in the air the position into which he should maneuver his plane to effect a landing into the wind. The T is rigid,- ly connected to a vertical shaft 4 carrying a worm gear 5 meshed with a worm 6 on the shaft 1 of an electric motor 8. By energizing the motor 8 alternately to revolve in opposite directions, the

wind T I may be rotated clockwise or counterclockwise to change its position.

The shaft 4, extending above the T I, carries a commutator 9 comprising circular conductor sectors I and II insulated from each other and from the shaft 4 by insulation l2. Above the commutator the shaft terminates in a reduced diameter portion I3 upon which is oscillatably mounted an arrow I4 by-a sleeve I depending therefrom and telescoped on the portion I3 of the shaft.

A head I6 is clamped on the sleeve I5 and carries a depending resilient arm I'I insulated from the head I6 by a block of insulation I8 and carrying at a lower portion thereof a roller type brush I9 adapted to roll on the commutator segments I I! and II. An arm 20 is pivotally supported on the arrow It as at 2| and on its lower end carries a contact 22 and is provided with a wind vane 23. The arrow I4 is adapted to be aligned with the wind direction to present the head 24 of the arrow to the wind and thus the vane 23 is at all times presented broadside to the wind whereby the arm may swing around the pivot 2|. Upon the attainment of wind velocity above a predetermined minimum, the wind pressure on the vane 23 will move the contact 22 into engagement with a contact 25 on the arm I1.

A change of wind direction will cause the arrow I4 to rotate on its vertical axis to a new position thereby rolling the brush I9 from a neutral position on a portion of the insulation I2 to one or the other of the segments [0 and II as illustrated in the drawing, and electric current may then flow correspondingly over one or the other of the wires 26 or 21 to the corresponding segment, thence by way of the brush I9 and contacts 25--22 to the arrow I4 and thence to ground as indicated at 28. By means to be described, the current thus flowing is utilized to actuate electro-magnetic switches whereby power from alternating current supply mains 29, 30 and 3| may flow through a line switch 32 through the motor 8, causing it to rotate in a predetermined direction, thereby moving the wind-T to a new position. Movement of the T is transmitted to the commutator segments Ill and II and will move them under the brush I9 until it rests upon the neutral position insulation l2 whereupon the said current willbe interrupted, power to the motor 8 will be discontinued, and the T will remain in its new position.

position. But if the wind be below the predetermined velocity at which it is immaterial in what direction an aviator may land on the field, the contacts 22-45 will remain open and automatic movement of the T I will be discontinued.

A potential transformer and rectifier apparatus or other source of direct current, such for example as a direct current generator or, a rotary converter is provided, indicated generally by the rectangle 33 supplied with energy from alternating current mains 34 through a line switch 35. When the roller brush I9 is moved to either of the seg ments ID or II as described, current may flow over a circuit including a ground connection 36, through the power supplying element of the rectiher 33, and through a switch winding 31 over the wire 21 to ground 28 or through a switch winding 38 over the wire 28 and to ground 28, the selection being determined by the direction in which the arrow I4 is moved from its normal position by a change of wind direction.

Assuming first that both of the windings 31 and 33 are de-energized by a corresponding position oi the arrow ,II, the switches 33 and 40 controlled respectively by the windings 31 and 38 will be in normal positions illustrated and current may flow by a wire ll through contact 42 and switch arm 43 of relay 38 and thence through switch arm 44 and contact 15 of relay 40, and by way of wire 46 to the point I! at which the current has two paths in parallel to ground, one path through a condenser 43 to ground at 43 and the other through a variable resistance 50, and winding 52 or a time controlled switch 53, and thence to ground at 54.

This current will be uni-directional as explained above and will charge the condenser 13 and also energize the winding 52 causing it to'raise its armature it moving the switch arm ll upwardly against a stop 51 and out of engagement with its contact BI. This will be the normal positions of the parts.

Upon energizing either of the windings 31 or ll, they will move their switch arms 43 and 44 to open the circuit at either the contact 42 or the contact ll interrupting the supply of current to the point 41. Thereupon the condenser ll begins to discharge causing current to flow in the local circuit from the condenser ll, through the resistance 50, winding I2 and back to the condenser by way of grounds N and I3, maintaining the winding I2 energized sufficiently to hold the arm I against the stop 51. The discharge cur-' rent gradually diminishes and after a predetermined time interval is no longer sumcient in the winding '2 to hold the switch 52 open and at the end of that interval it closes. The extent of this time can be predetermined by the capacity of condenser ll and the adjustment of the variable resistance It.

Assuming now that the arrow ll moves from the neutral position on the insulation portion II, to the segment which will cause energization of the relay winding 31 as above described, the switch 58 will engage the contact 58 and then the circuit will be completed through the arm and contact and by way of a wire 65 to another of the supply mains 30. The switch 62 will thereby be closed and power current may flow through the main switch 32 and by wire 30 through the lower bar 68 of the switch 52 and thence by wire 81 to the motor; and current may also flow from the supply main 29 through the upper bar 88 of the switch 62, and thence by wire 69 to the motor. Current may at all times be supplied from the main 3! to the motor.

The motor will thus be started and will turn the rolling upon the neutral insulation portion l2 whereupon the relay 3! will be restored to its normal position, tie-energizing the winding BI and causing the motor current to be broken at the upper and lower bars 38 and 68 of the reversing switch 62 whereupon the motor will stop.

If, at any time during the running of the time interval, the arrow l4 should de-energize the winding 31, the switch arm 43 will fall and engage the contact 42 and the condenser II will have its charge restored before the switch 53 closes, and the switch 53 will be prevented from closing.

I have found that a suitable interval is six seconds or less and this can readily be obtained without undue size and expense of the parts producing the time interval. These parts may be considered as a time interval producing unit and are identified as enclosed within the broken line rectangle 10.

If, instead of energizing the winding 31, the arrow eifects energization of the winding 28, the switch arm 44 will be raised, breaking current to the time delay unit 'lllat the contact I and starting the time interval. Unless the switch arm 44 is restored by de-energization of the winding 33 before the time interval has run, current may flow from the wire 30 through the winding H of the other reversing switch 12 and by way of a wire 13 may flow to the contact ll through the switch arm 44 and by way of wire ll as'bei'ore through the switch arm 58 and contact II and wire 6!, thereby closing the reversing switch 12. Power current will then flow from supply main Ill through the lower bar 1! to the current main 8!, and from supply wire 29 through the upper bar 18 to motor supply main IT. This will energize the motor I in the reverse of its former direction and move the T reversely for the purposes above set forth.

The operation of the control system and apparatus will now be apparent. The fluctuatingly moving arrow may alternately energize the wires 21 and 23, alternately operating the relays I! and M to alternately operate the reversing switches 62 and I2 to operate the motor I in alternate directions to swing the T l in one direction or the other. In each instance, however. upon the operation of a relay 3! or 40, current supplied to the time delay system 10 is interrupted to initiate discharging of the condenser II and start the time interval running. If the fluctuating arrow M is not restored by a reverse fluctuation before the end of the time interval, the switch 53 will close and permit the motor to be energized as stated but if the fluctuating arrow returns before the time interval is completed, the corresponding relay will be deenergized to eflfect opening of the motor circuit on the corresponding reversing switch 62 or 12 before cur- 7s rent has flowed therethrough to the motor, and the condenser 48 will again be charged preparatory to the initiation of another time interval. The T I, therefore, is not moved by the motor during the fluctuating movement of the arrow l4 unless and until it remains in a fluctuated position on one side or the other of neutral for the predetermined time interval or longer, and even then is moved only sufliciently to restore the arrow relatively to the neutral position.

It will now be clearly apparent furthermore that the reversing switches 62 and 12 will remain open and inert because the windings GI and 1| thereof are not energized during fluctuations of the arrow l4 and alternate operations of the relays 39 and 40 except when the time interval has completely run. Thus in the normal operation of the apparatus, the only parts which move repeatedly as the arrow l4 fluctuates will be the relays 39 and 40, and these may be made small and quiet in operation so that the entire system will be in general inert and inactive except when it functions to move the massive T I.

In connection with the time interval producing unit 10, means may be provided to indicate the operation thereof. In the preferred form, I place an ammeter 11 in series with the winding 52, the indicating finger 18 of which will indicate maximum of fiow of current in the normal state of the apparatus. When supply to the unit 10 is broken at the contact 45 or 42, and the time interval begins to run, the decaying current to the winding 52 will be indicated on the instrument 12 by gradual movement toward the left of the finger 18, the finger reaching an extreme position toward the left when the time interval has been completed. By such means the time interval may be timed and accordingly predetermined by adjusting the resistance 50; and likewise the instrument will indicate whether the system is properly operating or has become defective.

In place of the instrument 11, a glow discharge lamp 19 may be employed and will indicate by the intensity of the illumination thereof the amount of current flowing and thus will indicate not only whether the system is properly operating but also the length of the time interval in a manner similar to that described for the instrument 11/ In Fig. 2 I have illustrated a modification in which, instead of the condenser 48, a storage battery 80 is employed. Any suitable number of cells may be provided for the desired voltage and the plates of the battery may be of relatively small amperage capacity so as to substantially completely discharge in the desired time interval, the time interval being again adjustable by the resistance 50 which will vary the discharge amperage.

My invention is not limited to the exact details of construction shown and described. Modifications and changes may be made without departing from the spirit of my invention or sacrificing thereof, an electric energy storage means, circuit I means and a control current source for energizing the normally unoperated switch in parallel with the energy storage means to operate the normally unoperated switch and hold it operated under control of the two-position switch in its other position, whereby when the two-position switch moves to said other position, the normally unoperated switch will be operated and held operated and the energy storage means will be charged and remain charged, and the first switch will be restored or remain unoperated, and when the two-position switch moves to the said one position, the energy storage means will discharge through the winding of the normally unoperated switch and permit it to move to unoperated position after a predetermined time interval, whereupon the first electro-magnetic switch may operate under joint control of the normally unoperated switch and of the said two-position switch in the said one position thereof.

2. An electric system for effecting operation of a first electro-magnetic switch in response to movements of a two-position switch having normally closed and normally open contacts, comprising a normally closed electro-magnetic switch controlling energization of the first switch Jointly with the two-position switch through the normally open contacts thereof, an electric energy storage means, circuit means and a control current source for energizing the normally closed switch winding in parallel with the energy storage means to open the normally closed switch and hold it open under control of the normally closed contacts of the two-position switch, whereby when the two-position switch moves to close the normally open contacts, the normally closed switch will be opened and held opened and the energy storage means will be charged and remain charged and the first switch will be unenergized, and when the two-position switch moves to close the normally open contacts, the energy storage means will then discharge through the winding of the normally closed switch and permit it to close after a predetermined time interval, whereupon the first electro-magnetic switch may be energized under the joint control of the normally closed switch and of the now closed normally open contacts of the two-position switch.

3. In an electric system, a main circuit to be controlled, at first electro-magnetic switch for controlling the main circuit, a two-position switch having an unoperated and an operated position, a delayed operation electromagnetic switch having a normally unoperated position in which jointly with the two-position switch in its operated position controls operation of the first switch, the winding of the delayed operation switch having an electric energy storage means in parallel therewith and both the energy storage means and the winding of the delayed operation switch being controlled by the two-position switch in its unoperated position, whereby when the two-position switch is unoperated, the energy storage means and the winding of the delayed operation switch may be energized and remainenergized to operate the delayed operation switch to prevent operation of the first switch, and, upon movement of the two-position switch to its operated position, energy from the energy storagemeans may discharge through the winding of the delayed operation switch permitting it to operate after a predetermined interval and thereupon to cause, jointly with the two-position switch in its operated position, operation of the first switch.

4. In an electric system, a main circuit to be controlled, a first electromagnetic switch for controlling the main circuit, a two-position switch having normally closed and normally open contacts, a delayed operation electromagnetic switch the normally closed contacts closed, the energy storage means and the winding of the delayed operation switch may be energized and remain energized to open the contacts of the delayed operation switch to prevent energization of the winding of the first switch, and,- upon movement of the two-position switch to close the normally open contacts and open the normally closed contacts, energy from the energy storage means may discharge through the winding of the delayed operation switch permitting it to close after a predetermined time interval and thereupon to cause energization of the winding 01' the first switch through the contacts of the delayed operation switch and the now closed normally open contacts of the two-position switch.

ROSS J. PLAIBTED. 

